feat: add support for laravel 8

Based on brozot#217

composer.json

@@ -11,15 +11,15 @@
         }
     ],
     "require": {
-        "php": "^7.2.5",
-        "illuminate/support": "^6.0|^7.0",
+        "php": "^7.2.5|^8.0",
+        "illuminate/support": "^6.0|^7.0|^8.0",
         "guzzlehttp/guzzle": "^6.3|^7.0",
         "monolog/monolog": "^1.12|^2.0"
     },
     "require-dev": {
-        "mockery/mockery" : "^1.3.1",
-        "phpunit/phpunit" : "^8.4|^9.3",
-        "laravel/laravel": "^6.0|^7.0",
+        "mockery/mockery" : "^1.3.1|^1.4.4",
+        "phpunit/phpunit" : "^8.4|^9.3|^9.5",
+        "laravel/laravel": "^6.0|^7.0|^8.0",
         "php-coveralls/php-coveralls": "^2.0"
     },
     "autoload": {

src/FCMManager.php

@@ -9,13 +9,29 @@ class FCMManager extends Manager
 {
     public function getDefaultDriver()
     {
-        return $this->app[ 'config' ][ 'fcm.driver' ];
+        return $this->getContainer()[ 'config' ][ 'fcm.driver' ];
     }
 
     protected function createHttpDriver()
     {
-        $config = $this->app[ 'config' ]->get('fcm.http', []);
+        $config = $this->getContainer()[ 'config' ]->get('fcm.http', []);
 
         return new Client(['timeout' => $config[ 'timeout' ]]);
     }
+
+    /**
+     * Get the app container
+     *
+     * @return \Illuminate\Contracts\Container\Container
+     */
+    public function getContainer()
+    {
+        // Laravel 7.x, 8.x support
+        if (isset($this->container)) {
+            return $this->container;
+        }
+
+        // "app" Does not exist anymore in 8.x
+        return $this->app;
+    }
 }